What Is Tin Chloride?
Tin chloride is a tin chloride that exists in two forms: tin dichloride with an oxidation number of 2 and tin tetrachloride with an oxidation number of 4.
It is a very strong reducing agent, and when oxidized in air, it changes to tin oxide. Tin dichloride is a colorless crystal, while tin tetrachloride is a colorless liquid. Besides being widely used in industrial applications, tin tetrachloride is one of the most important raw materials in the manufacture of tin.
Both tin dichloride and tin tetrachloride are designated as “deleterious substances” under the Poisonous and Deleterious Substances Control Law. Since they are toxic to the human body, care must be taken when handling them.
Uses of Tin Chloride
1. Tin Dichloride
An acidic aqueous solution of tin dichloride has strong reducing properties. Taking advantage of this property, tin dichloride is used as a reducing agent and reaction catalyst for water-soluble organic compounds and as an analytical reagent in the field of analytical chemistry.
Other applications that take advantage of its strong reducing properties include ink erasing, silver plating of mirrors, leather tanning agents, and as a raw material for mordant solutions used to stop color during dyeing.
2. Tin Tetrachloride
Tin tetrachloride is used in industrial applications as a raw material for the synthesis of organotin compounds, as a mordant, condensing agent, reaction catalyst, and conductive paint.
Properties of Tin Chloride
1. Tin Dichloride
Tin dichloride is represented by the chemical formula SnCl2 and has a molecular weight of 189.62. Its CAS number is 7772-99-8.
Tin dichloride has a melting point of 246°C, a boiling point, an initial distillation point, and a boiling range of 623°C, and no information on its flash point or explosive range. It is very soluble in water, with a solubility of 900 g/kg (at 20°C).
It decomposes when heated, producing toxic and corrosive gases. It is a strong reducing agent and reacts with oxidants (nitrates, peroxides, bases, etc.), so care should be taken when handling it.
2. Tin Tetrachloride
Tin tetrachloride has the chemical formula SnCl4, a molecular weight of 260.52, and CAS number 7646-78-8.
Tin tetrachloride has a melting point of -33 °C, a boiling point of 114.1 °C, a spontaneous combustion temperature above 654 °C, and no information on flash point or explosive range.
It is chemically stable under standard atmospheric conditions but reacts with aluminum, metals, oxides, air, and moisture. In case of fire, hydrogen chloride gas, tin oxides, and other toxic gases may be generated.
Other Information on Tin Chloride
1. How Tin Chloride Is Produced
Tin dichloride is produced by dissolving metallic tin in hydrochloric acid to form a dihydrate. The dihydrate is then reacted with acetic anhydride to form anhydrous tin dichloride.
Tin tetrachloride is generally produced by directly reacting metallic tin with chlorine gas, followed by distillation to produce tin tetrachloride.
2. Safety of Tin Chloride
Tin dichloride may cause respiratory irritation, and there is a risk of liver, kidney, and blood system damage due to long-term or repeated exposure. Tin dichloride is highly toxic to aquatic organisms, so care should be taken when handling and disposing of it.
Tin tetrachloride poses a risk of serious skin and eye damage, as well as respiratory irritation, and may be life-threatening if inhaled. It is also harmful to aquatic organisms due to long-term persistent effects.
In case of fire, avoid stick discharge and extinguish with water spray, foam, powder extinguishing media, carbon dioxide, and dry sand. Firefighters should wear appropriate air respirators and chemical protective clothing when extinguishing fires due to the risk of irritant, corrosive, and toxic gases being generated.
3. Handling Methods
As with all tin dichloride and tin tetrachloride, appropriate protective gloves, protective clothing, protective glasses, and protective masks should be worn when working with tin dichloride and tin tetrachloride. Avoid eating, drinking, and smoking when handling, and wash skin after handling.
Tin dichloride should be handled in workplaces with local exhaust ventilation or total ventilation, and care should be taken not to inhale dust, vapor, or spray. Tin tetrachloride should be handled under inert gas because it reacts with air and moisture. Wearing filter-type respiratory protection is recommended.
4. Storage Methods
Tin dichloride should be stored in a well-ventilated area with the container tightly closed and locked. Tin tetrachloride should be stored in appropriate material containers, such as those with corrosion-resistant or corrosion-resistant linings. In addition, since it reacts with moisture and oxygen, it should be sealed with an inert gas and stored in a cool dry place.